NK cells are an important component of the innate immune system that provide protection against viruses, intracellular bacteria and parasites. The major goal of our lab is to determine how NK cells are stimulated when they encounter pathogen-infected or transformed cells. In currently funded projects, we have focused our efforts on NK cell receptors that signal by distinct pathways. One family of NK cell receptors transmits signals by using the (immunoreceptor tyrosine-based activation motif) ITAM-bearing DAP 12, FceRI,/, and transmembrane adapter protein that activates the Syk and ZAP70 tyrosine kinase pathway. Another NK receptor, NKG2D, associates with the DAP 10 transmembrane adapter protein that binds and stimulates the PI3-kinase pathway. A third less well understood pathway of activation involves receptors using the cytoplasmic SAP-adapter protein. Positive signals transmitted by these activating receptors are countered by inhibitory receptors using immunoreceptor tyrosine-based inhibitory motifs (ITIM). The balance between these activating and inhibitory receptors regulates NK cell responses. These ongoing projects will benefit greatly by using the 'Glue' core resources, which will provide technologies and resources not available to our laboratory. In this project, we propose to determine the molecular consequences of NK cell activation by defined receptor pathways using the genomic and proteomic technologies uniquely available through this cooperative interaction. Specifically, we define the basis for the synergistic interactions observed by simultaneous ligation of the ITAM-based NK cell receptors and the DAP 10-mediated or SAP-mediated signaling receptors. Furthermore, studies will be designed to evaluate whether ITIM-based inhibitory receptors act to simply dampen the strength of signaling via these activation pathways (a quantitative influence) or if they qualitatively affect the signaling pathway (blocking certain downstream events, but leaving others active). Finally, because stimulation of macrophages through their Toll-like receptors (TLR) induces genes encoding ligands for the NKG2D receptor, we will explore the consequences of cognate interactions between NK cells and macrophages stimulated by microbial products. Additionally, we envision that the 'Glue' consortium will catalyze interactions with other participating labs with a common interest in innate immunity.